Moved SendOnly mode to ConfigurationBuilder

This also fixes #2101 and #1337 

### New usage of sendonly
NServiceBus Host:
```c#
public class Endpoint : IConfigureThisEndpoint {
    public void Customize(ConfigurationBuilder builder)
    {
        builder.UseTransport<Msmq>()
            .SendOnly();
    }
}
```

Self Hosting:
```c#
var bus = Configure.With(
    b => b.UseTransport<Msmq>()
        .UseSerialization<Xml>()
        .SendOnly())
    .CreateBus();
```